When you think of world-class parks, the first place that comes to mind might not be Tulsa, Oklahoma. But a growing band of donors orchestrated by one local foundation are hoping to change that with a massive riverfront project that is racking up millions in support from local families and corporations.

A Gathering Place for Tulsa will be one of the largest and priciest privately funded parks in the United States when it’s finished, with Phase I clocking in at an estimated $300 million. The multi-purpose, riverfront park is mostly the doing of the George Kaiser Family Foundation, a supporting organization of the Tulsa Community Foundation, and the primary donor and mastermind of the plan.

The wealth behind GKFF comes from the oil and gas fortunes of George B. Kaiser, a lifelong resident of Tulsa, a primary owner of the parent corporation of the Kaiser-Francis Oil Company, and a major shareholder in several oil, gas, mining and tech companies.

Of the Phase I costs, the Kaiser Foundation has committed $200 million, including $50 million to buy the initial 66.5 acres of land involved and another $150 million in construction costs. The foundation is planning to raise $150 million in private funds for the project, and the results so far have been a pretty crazy parade of wealthy Oklahoma donors—mostly corporations, many dealing in oil and gas—cutting big checks.

For example:

Williams Companies, a Tulsa energy company, has pledged $16 million.

QuikTrip, a convenience store chain based in the city, is giving $12.5 million.

ONEOK, based in Tulsa and one of the largest natural gas companies in the country, pledged $10 million.

Magellan, Unit Corps, and Laredo Petroleum are among the other corporations that have made multi-million dollar donations.

A number of foundations and individual donors have made sizable contributions as well. The Chapman Foundation gave $10 million, and there have been several $5 million grants, including from the Charles and Lynn Schusterman Family Foundation, the FW Murphy Family foundation, Charles and Peggy Stephenson, and the Helmerich Trust.

Apparently The Gathering Place is the project for Oklahoma companies and wealthy community members to have their name attached to, with Kaiser having raised more than $100 million toward its goal so far. Only $35 million in public dollars are being invested in the project so far.

A Gathering Place will be a massive riverfront park, connecting three adjacent parcels to the existing park system, with plans that include a series of gardens and lawns, a pond and boathouse, a skate park, and an “adventure play garden.”

The space is being designed by Michael Van Valkenburgh Associates Inc., a landscape architecture firm that designed the Allegheny Riverfront Park, the Hudson River Park, and Brooklyn Bridge Park Piers 1, 5 and 6.